MOVEMENT AND THE MOTOR AREAS OF THE FRONTAL LOBES

FUNCTIONAL NEUROANATOMY OF THE RIGHT PRE-FRONTAL LOBE

THE FRONTAL LOBE PERSONALITY

The frontal lobes serve as the "Senior Executive" of the brain and personality, acting to process, integrate, inhibit, assimilate, and remember perceptions and impulses received from the limbic system, striatum, temporal lobes, and neocortical sensory receiving areas (Fuster 1997; Joseph 1986a; Koechlin et al., 1999; Milner and Petrides 1984; Passingham 1993; Selemon et al. 1995; Shallice and Burgess 1991; Stuss 1992; Stuss and Benson 1986; Strub and Black 1993; Van Hosen et al., 1996). Through the assimilation and fusion of perceptual, volitional, cognitive, and emotional processes, the frontal lobes engages in decision making and goal formation, modulates and shapes character and personality and directs attention, maintains concentration, and participates in information storage and memory retrieval (Dolan et al., 1997; Joseph, 1986a, 1988a, 1999a; Kapur et al., 1995; Passingham, 1997; Posner & Raichle, 1994; Tulving et al., 1994).

The frontal neocortex is "interlocked" with the limbic system, striatum, and the primary and secondary receiving areas via converging and reciprocal connections, and receives verbal and ideational impulses transmitted from the multi-modality associational areas including Wernicke's area and the inferior parietal lobule (Cavada 1984; Fuster 1997; Jones and Powell 1970; Goldman-Rakic 1995, 1996; Passingham, 1993, 1997; Pandya & Yeterian 1990; Petrides & Pandya 1988). It is thus able to act at all levels of information analysis.

THE FRONTAL LOBE PERSONALITY

With unilateral, bilateral, or even seemingly mild frontal lobe dysfunction patients may initially display an array of waxing and waning abnormalities including the "frontal lobe personality," i.e. tangentiality, childishness, impulsiveness, jocularity, grandiosity, irritability, increased sexuality, and manic excitement (Joseph, 1988a, 1999a; Lishman, 1973). Over fifty years of research and numerous case studies have consistently indicated that with significant frontal lobe pathology attentional functioning may become grossly comprised, behavior may become fragmented, and initiative, goal seeking, concern for consequences, planning skills, fantasy and imagination, and the general attitude toward the future may be lost.

The patient's range of interests may shrink, they may be unable to adapt to new situations or carry out complex, purposive, and goal directed activities, and lack insight, judgement, and common sense (Fuster 1997; Freeman and Watts 1942; Girgis 1971; Hacaen 1964; Joseph 1986a, 1988a, 1999a; Luria 1980; Passingham 1993; Petrie 1952; Stuss 1991; Stuss and Benson 1986). Conversely, when engaging in memory, planning, decision making, goal formation, and tasks requiring imagination, the frontal lobes become highly active--as demonstrated by functional imaging (Brewer et al., 1998; Passingham, 1997; Wagner et al., 1998; Dolan et al., 1997; Squire, et al,. 1992; Tulving et al., 1994; Kapur et al., 1995).

With massive trauma, stroke, neoplasm or surgical destruction (i.e. frontal lobotomy), patients may show a reduction in activity and take very long to achieve very little. They may be unconcerned about their appearance, their disabilities, and demonstrate little or no interest in self-care or the manner in which they dress, or even if their clothes are soiled or inappropriate (Bradford 1950; Broffman 1950; Freeman and Watts 1942; Petrie 1952; Strom-Olsen 1946; Stuss 1991; Stuss and Benson 1986; Tow 1955).

Although some patients demonstrate restlessness, impulsiveness, and flight of ideas, they may also tire easily, show careless work habits and a desire to get things over with quickly. As repeatedly documented following frontal lobotomy, they may immediately develop a tendency to lie in bed unless forcibly removed (Broffman 1950; Freeman and Watts 1942 1943; Rylander 1948; Tow 1955). Even with mild and subtle frontal lobe damage, patients may seem to take hours to get dressed, to finish their business in the bathroom, or to shop and purchase simple items. For example, patients may spend hours in the bathtub playing with the bubbles. A curious mixture of obsessive compulsiveness and passive aggressiveness may be suggested by their behavior.

In severe cases, compulsive utilization of utensils and tools may occur, as well as distractability and perserveration. For example, following frontal lobotomy, "sometimes a pencil and a piece of paper will be enough to start an endless letter that may end up with the mechanical repitition of a certain phrase, line after line and even page after page" (Freeman and Watts 1943, p. 801).

Even with "mild" to moderate frontal lobe injuries patients may initially demonstrate periods of tangentiality, grandiosity, irresponsibility, laziness, hyperexcitability, promiscuity, silliness, childishness, lability, personal untidiness and dirtiness, poor judgment, irritability, fatuous jocularity, and tendencies to spend funds extravagantly. Unconcern about consequences, tactlessness, and changes in sex drive and even hunger and appetite (usually accompanied by weight gain) may occur, coupled with a reduction in the ability to produce original or imaginative thinking.

DISINHIBITION AND IMPULSIVENESS

Following lobotomy or massive or even mild frontal injuries patients may become emotionally labile, irritable, euphoric, aggressive, and quick to anger, and yet be unable to maintain a grudge or a stable mood state as they rapidly oscillate between emotions (Bradford 1950; Greenblatt 1950; Joseph 1986a, 1999a; Rylander 1939; Strom-Olsen 1946; Stuss 1991; Stuss and Benson 1986). Depending on the degree of damage, they may become unrestrained, overtalkative, and tactless, saying whatever "pops into their head", with little or no concern as to the effect their behavior has on others or what personal consequences may result (Broffman 1950; Bogousslavasky et al. 1988; Freeman and Watts 1943; Joseph 1986a, 1999a; Luria 1980; Miller et al. 1986; Partridge 1950; Rylander 1939, 1948; Strom-Olsen 1946).

With severe injuries patients may seem inordinantly disinhibited and influenced by the immediacy of a situation, buying things they cannot afford, lending money when they themselves are in need, and acting and speaking "without thinking." Seeing someone who is obese they may call out in a friendly manner, "Hey, fatty", and comment on their presumed eating habits. If they enter a room and detect a faint odor, its: "Hey, who farted?"

Following severe injuries there may be periods of gross disinhibition which may consist of loud, boisterous, and grandiose speech, singing, yelling, and beating on trays. The destruction of furniture and the tearing of clothes is not uncommon. Some patients may impulsively strike doctors, nurses, or relatives and thus behave in a thoroughly labile, aggressive, callous and irresponsible manner (Benson and Geschwind 1971; Freeman and Watts 1942, 1943; Joseph 1986a, 1999a; Strom-Olsen 1946; Stuss and Benson 1986).

One patient, with a tumor involving the right frontal area, following resection, attempted to throw a fellow patient's radio through the window because he did not like the music. He also loudly sang opera in the halls. Indeed, during the course of his examination he would frequently sing his answers to various questions (Joseph 1986a).

Impulsiveness can also be quite subtle. Luria (1980, p. 294), describes one patient with a slowly growing frontal tumor "whose first manifestation of illness occurred when, on going to the train station, he got into the train which happened to arrive first, although it was going in the opposite direction."

UNCONTROLLED LAUGHTER AND MIRTH

Frontal lobe patients can act in a very childish and puerile manner, laughing at the most trivial of things, making inappropriate jokes, teasing, and engaging total strangers in hillarious conversation (Ackerley 1935; Freeman and Watts 1942, 1943; Kramer 1954; Luria 1980; Petrie 1952; Rylander 1939, 1948; Stuss and Benson 1986). Pathological laughter, joking, and punning may occur superimposed upon a labile effect. Many are vastly amused by their own jokes (Ironside 1956; Kramer 1954; Martin 1950). They can be quite funny, but often they are not!

In part, frontal lobe humor is a function of tangentiality and disinhibition. Loosely connected ideas are strung together in an unusual fashion. The tendency to exaggerate and to impulsively comment upon whatever draws their attention is also contributory, and their humor and laughter may have a contagious quality.

Nevertheless, rather than funny, frontal patients may seem crude and inappropriate. They may laugh without reason and with no accompanying feelings of mirth. These disturbances were in fact documented over 50 years ago. Kramer (1954) for example, describes 4 cases of uncontrollable laughter after lobotomy. They were unable to stop their laughter on command or upon their own volition. The laughter would come on like spells, occurring up to a dozen times a day, and/or continue into the night, requiring sedation in some cases. In these instances, however, the laughter had no contagious aspects but seemed shrill and "frozen." When questioned about the laughter the patients either confabulated a reason for their mirth, or seemed completely perplexed as to the cause.

THE RIGHT PRE-FRONTAL LOBE AND THE REGULATION OF AROUSAL

The right cerebral hemisphere is clearly dominant in regard to the mediation and control over most aspects of social-emotional functioning (chapter 10). There is also a variety of findings which strongly suggest that the so called alerting/arousal vigilance network is localized to the right frontal lobe (Posner & Raichle, 1994), and that the right frontal lobe exerts bilateral influences on arousal (DeRenzi & Faglioni, 1965; Heilman & Van Den Abell, 1979, 1980; Joseph, 1982, 1986a, 1988a, 1999a; Konishi, et al., 1999; Tucker, 1981).

For example, the intact, normal right hemisphere is quicker to react to external stimuli, and has a greater attentional capacity compared to the left (Dimond, 1976, 1979; Heilman & Van Den Abell, 1979; Jeeves & Dixon, 1970; Joseph, 1988ab). In split brain studies the isolated left hemisphere tends to become occasionally unresponsive, suffers lapses of attention, and is more limited in attentional capacity as compared to the right which attends to both the left and right half of visual, auditory, and tactile space (Dimond 1976, 1979; Joseph 1986a, 1988ab). Indeed, visual and somesthetic stimuli, or active touch exploration with either the right or left hand, elicits evoked EEG responses preferentially and of greater magnitude over the right hemisphere and right frontal lobe (Desmedt 1977).

The right hemisphere also becomes desynchronized (aroused) following left or right sided stimulation (indicating it is bilaterally responsive), whereas the left brain is activated only with unilateral (right side) stimulation (Heilman & Van Dell Abell, 1980). In fact, the right frontal lobe and hemisphere responds more quickly even to stimuli appearing on the right side (Dimond 1976 1979; Heilman and Van Den Abell 1979, 1980; Jeeves and Dixon 1970). In consequence, if the right frontal lobe (or hemisphere) is injured, the left frontal lobe is unable to attend to events occurring on the left side of the body, which results in unilateral left-side neglect.

The right frontal lobe is also larger than the left suggesting a greater degree of interconnections with other brain tissue, and it appears to exert bilateral inhibitory influences on attention and arousal (Cabeza and Nyberg 1997; DeRenzi and Faglioni 1965; Dimond 1976 1979; Heilman and Van Den Abell 1979, 1980; Jeeves and Dixon 1970; Joseph 1986a, 1988ab; Konishi et al., 1999; Pardo et al. 1991; Tucker 1981). For example, as based on functional imaging, it has been found that when performing a "go/no-go task" and the Wisconsin Card Sort--tasks requiring the inhibition of irrelevant or erroneous responses, activity significantly increases in the right inferior frontal lobe, and that this was the case irrespective of if the human subjects used the right or left hand (Konishi et al., 1999). By contrast, the left frontal region appears to exert unilateral excitatory influences which promotes right sided motor control and speech expression.

However, because the right frontal lobe appears to exert bilateral inhibitory influences, whereas the influences of the left are unilateral and excitatory, when the left frontal region is damaged, the right may act unopposed and there may be excessive left cerebral inhibition or reduced activity (e.g., Bench et al., 1995); for example, as manifested by speech arrest, depression, and/or apathy.

Nevertheless, because left cerebral excitatory influences are predominantly unilateral, with massive right cerebral damage, although the left hemisphere is aroused, the left is unable to activate the right half of the brain. This may result in unilateral inattention and neglect of the left half of the body and space (Heilman & Valenstein, 1972; Joseph, 1986a, 1988a; Na et al., 1999). That is, the patient's (undamaged) left hemisphere may ignore his of her left arm or leg, and if their neglected extremities are shown to them, may claim they belong to the doctor or a person in the next room. That such disturbances occur only rarely with left frontal or left hemisphere damage further suggests that the right hemisphere is able to continue to monitor events ocurring on either side of the body. Thus although the damaged left hemishere is hypoaroused (or inhibited by the right), there is little or no neglect.

However, with lesions involving the right frontal lobe, not only is there a loss of inhibitory control, but the left may act unopposed such that there is excessive excitement. The patient becomes disinhibited as manifested by speech release, confabulation, lability, and a host of impulsive disturbances which may wax and wane in severity.

As detailed below, mania, confabulation, hypersexuality, tagentiality, and impulsive, labile, disinhibited and inappropriate social and emotional behaviors are predominately associated with right frontal dysfunction (Bogousslavsky et al. 1988; Clark and Davison 1987; Cohen and Niska 1980; Cummings and Mendez 1984; Fischer et al. 1995; Forrest 1982; Girgis 1971; Jack et al. 1983; Jamieson and Wells 1979; Joseph 1986a, 1988a, 1999a; Kapur and Coughlan 1980; Lishman 1973; Miller et al. 1986; Oppler 1950; Rosenbaum and Berry 1975; Shapiro et al.1981; Starkstein et al. 1987; Stern and Dancy 1942; Stuss and Benson 1986); a function of loss of inhibitory control as well as its role in all aspects of emotion. In fact, and as originally pointed out by Lisman (1968, 1973), injuries to the right frontal lobe are clearly associated with what has been described as the "frontal lobe personality," including, in the extreme, the development of a full blown manic psychosis coupled with disinhibited sexuality.

DISINHIBITED SEXUALITY

In some cases following frontal lobe damage patients may engage in inappropriate sexual activity (Benson and Geschwind 1971; Brutkowski 1965; Freeman and Watts 1942, 1943; Girgis 1971; Leutmezer et al., 1999; Lishman 1973; Miller et al. 1986; Strom-Olsen 1946; Stuss and Benson 1986). One patient, after a right frontal injury began patronizing up to 4 prostitutes a day, whereas his premorbid sexual activity had been limited to Tuesday evenings with his wife of 20 years (Joseph 1988a). Another patient with a right frontal stroke propositioned nurses and would spontaneously reach out and fondle large breasted women (Joseph 1988a).

It is not unusual for a hypersexual, disinhibited frontal lobe injured individual to employ force. One individual who was described as quite gentle and sensitive prior to his injury, subsequently raped and brutalized several women. Similar behavior has been described following lobotomy. As stated by Freeman and Watts (1943, p. 805): "Sometimes the wife has to put up with some exaggerated attention on the part of her husband, even at inconvenient times and under circumstances which she may find embarrassing. Refusal, however, has led to one savage beating that we know of, and to an additional separation or two" (p. 805).

Curiously, in these situations Freeman and Watts (1943, p. 805) have suggested that "spirited physical self-defense is probably the best strategy of the woman. Her husband may have regressed to the cave-man level, and she owes it to him to be responsive at the cave-women level. It may not be agreeable at first, but she will soon find it exhilarating if unconventional."

Seizure activity arising from the deep frontal regions have also been associated with increased sexual behavior, including sexual automatisms, exhibitionism, gential manipulation, and masturbation (Leutmezer et al., 1999; Spencer, Spencer, Williamson, & Mattson 1983; Williamson, et al., 1985). One young man that I evaluated and who was subsequently found, with depth electrode recording, to have seizures emitting from the right frontal lobe, had been arrested over 7 times for exposing himself in public. His parents complained that he would sometimes walk around the house grabbing and exposing his genitals, and would sometimes even pee on the floor. In fact, while I was evaluating him as he lay in bed at the Yale Seizure Unit (VAMC) he suffered a seizure which involved the following sequence. He grunted loudly and his left arm shot out in a lateral arc. His left hand then returned to his body and he began to fiddle with the buttons of his pajamas continuing in a downward motion until he reached his penis which he then took in his hand and began to squeeze. As I looked on, he suddenly began to urinate and with such force that I was nearly sprayed with urine. Fortunately, I deftly escaped by leaping to the side and against the wall which put me well out of his range.

By contrast, a young woman I examined with right frontal-temporal seizures would spread her legs and engage in pelvic thrusting, coupled with grunting, lip licking and tongue protrusion. Currier et al., (1971), have also reported pelvic thrusting and moaning, and sex appropriate vocalizations, with temporal lobe seizures.

However, according to Leutmezer et al., (1999) and as based on prolonged scalp-EEG monitoring, sexual automatisms, such as "sexual hypermotoric pelvic or truncal movements are common in frontal lobe seizures," whereas "discrete genital automatisms, like fondling and grabbing the genitals are more common in seizures involving the temporal lobe." Presumably, the results of Leutmezer et al., (1999) differ from that of Currier, et al., (1971), Joseph (1988a, 1999a), Spencer et al., (1983), and Williams et al., (1985), due to their use of scalp rather depth electrodes which are more sensitive and exacting. On the other hand, temporal lobe/hippocampal sclerosis and atrophy were also documented in the Leutmezer et al. (1999) study.

Nevertheless, given the close functional association between the frontal and temporal lobes, and the fact that even a frontal seizure can propagate to the amygdala and thus involve the temporal lobe, perhaps the dysfunctional differences in abnormal sexual behavior are due to seizure origin and the subsequent spread of seizure activity.

Indeed, insofar as the behavior involves fondling and grabbing, the hands are being employed, and the hands are generally represented along the medial walls, within the SMA, cingulate, and along the lateral surface of the frontal lobe (see below), whereas truncal movements are more the province of the striatum with which the amygdala is intimately interconnected. Indeed, even with complete destruction of the anterior temporal lobe human and non-human primates may fondle their genitals and masturbate--a common components of the Kluver-Bucy syndrome (see chapter 13).

However, as the amygdala has been removed bilaterally, then this part of the brain cannot be directing hand-movements toward the genitals, which thus implicates the frontal lobes. Although this issue cannot be resolved here, it is nevertheless rather obvious than frontal-temporal seizures can produce abnormal and/or inappropriate sexual behavior.

There is also some evidence for functional laterality in regard to sexual automatisms and abnormal sexual behavior. In most instances, "sexual" seizures are associated with right frontal seizure foci (Joseph 1988a; Spencer et al. 1983). However, patients may also become hyposexual (Greenblatt 1950; Miller et al. 1986), especially with left frontal injuries, and/or experience genital pain with left temporal seizures (Leutmezer et al., 1999).

MANIA

When the right orbital and/or right lateral convexity are damaged, behavior often becomes inappropriate, labile, and disinhibited. Individuals may become hyperactive, distractable, hypersexual, tangential, delusional, and confabulatory (Bogousslavsky et al. 1988; Clark and Davison 1987; Cohen and Niska 1980; Cummings and Mendez 1984; Joseph,1986a, 1988a, 1999a; Lishman 1973; Robinson and Downhill 1995; Starkstein et al. 1987). Although laughing and joking one moment, these same patients can quickly become irritated, angered, enraged, destructive, or conversely tearful and depressed with slight provocation. That is, the patient may present with manic-depressive symptoms, with mania predominating. Hence, manic-depression (bipolar affective disturbances) may be due to waxing and waning abnormalities involving the right and left frontal lobes.

Mania and manic-like features have been reported in many patients with injuries, tumors, and even seizures involving predominantly the frontal lobe and/or the right hemisphere (Bogousslavsky et al. 1988; Clark and Davison 1987; Cohen and Niska 1980; Cummings and Mendez 1984; Forrest 1982; Girgis 1971; Jack et al. 1983; Jamieson and Wells 1979; Joseph 1986a, 1988a, 1999a; Lishman 1973; Miller et al. 1986; Oppler 1950; Robinson and Downhill 1995; Rosenbaum and Berry 1975; Starkstein et al. 1987; Stern and Dancy 1942).

One frontal patient described as formerly very stable, and a happily married family man, became excessively talkative, restless, grossly disinhibited, sexually preoccupied, extravagantly spent money and recklessly purchased a business which soon went bankrupt (Lishman 1973).

In another case, a 46-year old woman was admitted to the hospital and observed to be careless about her person and room, and incontinent of urine and feces. She slept very little and acted in a hypersexual manner. Her symptoms had developed several months earlier when she began accusing a neighbor of taking things she had misplaced. She also would confront him and strip off her clothes. She began going about in just a slip and bra, and informed people she was descended from queens, was fabulously wealthy, and that many men wanted to divorce their wives and marry her. During her hospitalization she was frequently quite loud, disoriented to time and place, and extremely tangential, jumping from subject to subject. After several years she died and a meningioma involving the orbital surface of the right frontal lobes was discovered (Girgis 1971).

I have examined 19 male and five female patients who developed mania after suffering a right frontal stroke or trauma to the right frontal lobe. All but four of the males had good premorbid histories and had worked steadily at the same job for over 3-5 years (e.g. Joseph, 1986a, 1988a). Following their injuries all developed delusions of grandeur, pressured speech, flight of ideas, decreased need for sleep, indiscriminant financial activity or irresponsibility, emotional lability, and increased libido, including, in one case, persistent sexual overtures coupled with genital exposure, to the patient's sisters and mother.

One formerly very conservative engineer with over 20 patents to his name suffered a right frontal injury when he fell from a ladder. He became sexually indiscriminate and reportedly patronized up to 3 prostitutes a day, whereas before his injury his sexual activity was limited to once weekly with his wife. He also spent money lavishly, suffered delusions of grandeur, camped out at Disney Land and attempted to convince personnel to fund his ideas for a theme park on top of a mountain, and at night had dreams where the Kennedy's would appear and offer him advice --and he was a republican!

EMOTIONAL & PROSODIC SPEECH

Right frontal injuries are thus associated with disinhibited states, including manic neuro-psychosis coupled with disturbances of thought and speech. Although language per se, is not aphasic, speech may be rushed, contaminated with unusual, tangential, and delusional ideas, and in some cases, melodic control over speech appears to be lost, such that the patient's melody of voice may not correspond with or parallel what is being said; e.g. they may be saying one thing, but by their labile tone of voice, seem to be meaning something else altogether.

Although language is usually discussed in regard to grammar and vocabulary, it is also emotional, melodic and prosodic --features which enable a speaker to convey and a listener determine, intent, attitude, feeling and meaning (chapters 10, 15). A listener comprehends noy only what is said, but how it is said--what a speaker feels.

Feeling and attitude are conveyed through the melody (musical qualities), inflection, intonation, and prosody of one's voice, and by varying the pitch, inflection, timbre, stress contours, melody, as well as the rate and amplitude of speech --capacities predominantly mediated by the right half of the cerebrum (see chapter 10).

Patients with severe forms of Broca's expressive aphasia are unable to discourse fluently. However, they may be capable of swearing, making statements of self-pity, praying, singing, and even learning new songs (Gardner 1975; Goldstein 1942; Gorelick and Ross 1987; Joseph 1988a; Ross 1981; Smith 1966; Smith and Burklund 1966; Yamadori, Osumi, Mashuara, and Okuto, 1977)--although in the absence of music they would be unable to say the very words they had just sung. This is because the ability to produce non-linguistic and musical/emotional sounds is mediated by the undamaged right frontal lobe and limbic nuclei (Gardner 1975; Gorelick and Ross 1987; Joseph 1988a; Ross 1993; Shapiro and Danly 1985). Indeed, just as the left frontal convexity (i.e. Broca's area) subserves the syntactical, temporal-sequential, motoric, and grammatical aspects of linguistic expression (Foerster 1936; Fox 1995; Goodglass & Kaplan, 2000; LeBlanc 1992; Petersen et al. 1988, 1989; Sarno, 1998), there is a homologous region within the right frontal area which mediates the expression of emotional and melodic speech (Gorelick and Ross 1987; Joseph 1982, 1988a, 1999a; Ross 1981, 1993; Shapiro and Danly 1985).

With massive damage involving the right frontal melodic-emotional speech area, speech may become flat and monotonous, or conversely, the ability to alter or convey melodic and prosodic elements may become exceedingly abnormal and distorted. With extensive injuries to the right frontal lobe, patients may lose control over their voice and at times may sound as if they are crying, wailing, or screeching. Such patients may loose the ability to engage in vocal mimicry or to accurately repeat various statements in an emotional manner (Gorelick and Ross 1987; Joseph 1988a; Ross 1981, 1993).

With mild damage, rather than severe distortions or a loss of melody, the intonational qualities of the voice can become mildly abnormal and patients may seem to be speaking with an odd midwestern-like accent--particularly with deep lesions of the right frontal area, perhaps involving the cingulate or basal ganglia. Prosodic distortion in the form of an unusual accent is sometimes seen in seizure disorders involving deep right frontal or frontal-temporal areas.

On the otherhand, with left frontal lesions some patients develop what sounds like an unlearned foreign accent, as if they were from Germany, France, etc. (Blumstein et al. 1987; Graff-Radford et al. 1986). This is due, in part, to distortions involving the pronounciation of vowells.

When damage is limited to this right frontal emotional-motor speech area, the ability to comprehend and understand prosodic-emotional nuances appears to be somewhat intact (Gorelick & Ross, 1987; Joseph, 1988a; Ross, 1993). However, with right temporal injuries, the ability to comprehend these nuances may be lost (Ross, 1993).

It is interesting to note, however, that despite the clinical, neuropsychological, and neuroanatomical evidence indicating that the right frontal and right temporal areas contribute to the production of emotional prosodic melodic speech, that functional imaging and blood flow studies have failed to display significant activity in these regions during language-related activities (Frost, et al., 1999; Pujol, et al., 1999)--a function perhaps, of the insensitivity of the tasks and/or measures employed in this regard.

TANGENTIAL, PRESSURED SPEECH & CIRCUMLOCUTORY SPEECH

Patients suffering from mania often display pressure, tangential and delusional speech. Likewise, with bilateral or right frontal lobe damage, speech may become pressured and tangential such that the patient rapidly diverges to other and unrelated topics (Joseph, 1986a, 1988a, 1999a). For example, when a patient with severe right orbital damage was asked if his injury affected his thinking, he replied, "yeah--it's affected the way I think--It's affected my senses--the only thing I can taste are sugar and salt--I can't detect a pungent odor--ha ha--to tell you the truth it's a blessing this way" (Blumer & Benson, 1975, p.197).

One frontal patient when asked what he received for Christmas replied, "I got a record player and a sweater." (Looking down at his boots) "I also like boots, westerns, popcorn, peanuts and pretzels." Another right frontal patient when asked in what manner an orange and a banana were alike replied, "fruit. Fruitcakes--ha ha--tooty fruity." When asked how a lion and a dog were alike he responded, "They both like fruit--ha ha. No. That's not right. They like trees--fruit trees. Lions climb trees and dogs chase cats up trees, and they both have a bark."

Tangentiality is in some manner related to impulsiveness as well as circumlocution. In contrast, patients with circumlocutious speech often have disturbances involving the left cerebral hemisphere and frequently suffer from word finding difficulty and sometimes receptive or expressive dysphasia. They experience difficulty expressing a particular idea or describing some need as they have trouble finding the correct words. Thus talk around the central point and only through successive approximations are able to convey what they mean to say.

Patients with tangential speech lose the point altogether. Instead, words or statements trigger other words or statements which are related only in regard to sound (e.g. like a clang association) or some obscure and ever shifting semantic category. Speech may be rushed or pressured and the patient may seem to be free associating as they jump from topic to topic.

Hence, in contrast to the aphasia, or speech arrest associated with left frontal injuries, right frontal lesions may result in speech release ("motor mouth"). Speech becomes disinhibited, pressure, and contaminated with tangential associations, and the patient may seem to be free associating as they jump from topic to topic. In the extreme speech becomes filled with confabulatory ideas.

CONFABULATION (DELUSIONAL & FALSE MEMORIES)

When secondary to right (or bilateral) frontal damage, speech may become exceedingly bizarre, delusional, and fantastical, as loosely associated ideas become organized and anchored around fragments of current experience.

For example, one patient, when asked as to why he had been hospitalized, denied that there was anything wrong, but instead claimed he was there to do some work. When asked what kind of work, he pointed to the air conditioning unit, and stated: "I'm a repair man. I'm here to fix the air conditioner. Now, if you'd please excuse me. I've got work to do."

A 24 year old store cleark who received a gunshot wound (during the course of a robbery) which resulted in destruction of the right inferior convexity and orbital areas, attributed his hospitalization to a plot by the government to steal his inventions (Joseph 1986a). He claimed he was a famous inventor, had earned millions of dollars and had even been on TV. When it was pointed out that he had undergone surgery for removal of bone fragments and the bullet, he pointed to his head and replied, "that's how they are stealing my ideas."

Another patient, formerly a janitor, who suffered a large right frontal subdural hematoma (which required evacuation) soon began claiming to be the owner of the business where he formerly worked (Joseph 1988a). He also alternatively claimed to be a congressman and fabulously wealthy. When asked about his work as a janitor he reported that as a congressman he had been working under cover for the C.I.A. Interestingly, this patient, also stated he realized what he was saying was probably not true. "And yet I feel it and believe it though I know it's not right."

Frontal lobe confabulation seems to be due to disinhibition, difficulties monitoring responses, withholding answers, utilizing external or internal cues to make corrections, accessing appropriate memories, maintaining a coherent line of reasoning, or suppressing the flow of tangential and circumstantial ideas (Fischer et al. 1995; Joseph 1986a,1988a, 1999a; Johnson, O'Connor and Cantor 1997; Kapur and Coughlan 1980; Shapiro et al.1981; Stuss et al. 1978; Stuss and Benson 1986). That is, since the right frontal lobe can no longer regulate information processing and the flow of perceptual and ideational activity, information that is normally filtered out and suppressed is instead expressed. In consequence, the Language Axis of the left hemisphere becomes overwhelmed and flooded by irrelevant, bizarre associations, leading sometimes to the expression of false memories, which the patient (that is, Broca's area) repeats (Joseph, 1982, 1986ab, 1988ab).

As noted, in some respects injuries involving the orbital frontal lobes can result in symptoms similar to those with right frontal injuries, including the production of confabulatory ideation. However, in contrast to right (or bilateral) frontal injuries which may result in the production of fantastical spontaneous confabulations where contradictory facts are ignored or simply incorporated, confabulatory responses associated with orbital injuries tend to be more restricted, transitory, and in some cases must be provoked (Fischer et al. 1995).

FRONTAL LOBE OVERVIEW	FRONTAL LOBE PERSONALITY	ORBITAL FRONTAL LOBES	RIGHT & LEFT FRONTAL
MEDIAL FRONTAL LOBE	FRONTAL MOTOR CONTROL	FRONTAL MEMORY RETRIEVAL	FRONTAL LOBE PSYCHOSIS

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